A large number of methods for producing fuel-air mixtures for reciprocating internal combustion engines are known, and many are patented. As far as Applicant is aware, previously disclosed methods all attempt to produce a fuel vapor mixed thoroughly with air. In many of these methods, fuel is heated, some instances to approximately a boiling point of the fuel, in order to convert the fuel to a gas prior to its induction into a combustion chamber. Virtually all attempt to minimize fuel droplet size based on the belief that fuel droplets in the fuel/air mixture cause inefficient combustion and generate more pollutants in the exhaust.
However, providing a stoichiometric fuel/air mixture wherein the fuel is in a vapor form also provides a readily explosive mixture. This becomes a problem when loading on an engine causes pressure increases in combustion chambers thereof sufficient to raise a temperature of the fuel/air mixture to or beyond its ignition point. This in turn causes the fuel/air mixture to explode all at once (rather than burning evenly in an outward direction from the spark plug), a condition commonly known as “knock” due to the knocking noise created, as bearings of the rotating parts of the engine are slammed together under the force of the explosion. As might be imagined, such a condition is deleterious to bearings and other parts of the engine, and greatly shortens engine life.
In accordance with the present invention (referred to in one embodiment hereinafter as “Star Tube”), an apparatus and process of fluid fuel treatment is provided, the process converting fuel into an aerosol having droplets of a predetermined maximum size with a minimum of vapor being generated in the induction air stream. The object of this invention is to allow internal combustion engines such as Otto-cycle engines, two-stroke engines, Wankel-type engines and other such engines that compress a fuel/air mixture just prior to sparked ignition to operate on a fuel-air mixture that is stoichiometrically correct without detonation, thus reducing fuel octane requirements for engines of a given compression ratio. This is achieved because fuel droplets “burn” at a slower rate than a gas/air mixture which explodes, thus reducing the tendency of an engine to knock. Here, it is believed that a fuel droplet within the aforementioned range burns in layers, so that as an outer layer of the fuel droplet is burned off, oxygen is temporarily depleted around the droplet. Oxygen then surrounds the droplet as combustion gases around the droplet expand and dissipate, allowing the next layer to burn off. This process is repeated until the fuel droplet is fully burned.
Engines such as diesel or other direct injection engines may also benefit from having the fuel particle size such that an even burn occurs although there is generally no knock problem with such engines.
It may also be possible that since, in the instant invention, fuel is initially sprayed into a generally confined tube, vapor saturation within the tube prevents further evaporation of the fuel droplets, causing the fuel droplets to be reduced in size mechanically rather than by evaporation as they travel to the combustion chamber. Here, as the fuel is sprayed into the tube, lighter, more volatile components of the fuel instantly evaporate and increase hydrocarbon vapor pressure within the tube, suppressing evaporation of the heavier hydrocarbon components in the droplets. The heavier-component fuel droplets are processed mechanically by the Star Tube until they reach a size sufficiently small so as to travel with a localized region of lighter-component fuel-saturated air into the combustion chamber.
In accordance with the foregoing, it is one object of the invention to provide apparatus for decreasing or eliminating engine knock and improving combustion by aerosolizing fuel into droplets of a predetermined size. It is another object of the invention to provide apparatus for generating a fuel/air mixture wherein the fuel is incorporated into the droplets to as great an extent as possible, with as little vapor as possible. It is yet another object of the invention to enable an internal combustion, spark ignition engine to operate normally without knock using a fuel of a lower octane rating than the engine is rated for. Other objects of the invention will become apparent upon a reading of the following appended specification.